Injecting food products (e.g., meats, poultry) with liquid, such as brine, has been used as a means of tenderizing the food product. However, when the injected liquid interacts with the muscle proteins, a portion of the injected brine, along with dissolved muscle proteins and natural juices and blood from the meat product, exudes from the food product during packaging. The exuded liquid blend “contaminates” the packaging film in the region to be sealed, in the sense that the exuded liquid interferes with the making of a strong and hermetic heat seal. As a result, a high percentage of the seals leak during initial heat sealing, after 24 hours, and/or when the product is shipped and arrives at its final destination. As high as 80% of the seals may leak. The high number of leaking seals results in costly product waste, a need for repackaging of the food product, and an increased risk of product contamination.
Microscopic analysis of seal areas contaminated with liquid blend reveals dried, brittle salt-like crystals, which may act as a physical barrier to intermolecular polymer diffusion across the seal area during heat sealing. Careful analysis of the seal strength of these seals reveals that the strength can be reduced up to and sometimes greater than 80% as compared to that of uncontaminated seals. Further, seal strength testing reveals that contaminated seals fail at the contaminated seal interface, while uncontaminated seals typically show failures outside of the seal area. Thus, the structural integrity of the packaging material is significantly limited by the contaminant in the seal area. The inherent strength of the packaging material no longer matters, as the contaminated seal becomes the “weak link”.
Some meat processors have circumvented the problem of high leaking seal rates by modifying the equipment used to package the food product. In particular, the platforms carrying the unsealed injected meat product in the packaging article are tilted to allow the liquid to slide off of the seal area and back into the meat product area. However, modifying the equipment is costly and does not provide a packaging material supplier with a competitive advantage.
Another solution to this problem of high seal failure rates is to provide an oversized packaging article. In this way, the seal can be made at a greater distance from the meat product thereby reducing the likelihood of contaminating the seal area. In addition, after sealing, there is less stress applied to the seal area from the meat product, particularly during abusive handling operations (e.g., packing the product in boxes or transporting the product). However, the resulting packaged product has reduced appearance or aesthetic value, since excess packaging material extends outward from the product. Also, the excess film provides an area where liquid collects, which is unsightly and can cause accelerated spoilage rates for the food product.
In light of the foregoing, it would be desirable to provide a packaging article having hermetic seals which exhibit fewer leaks and/or greater seal strength in the packaging of a food product having an added liquid. The article should also be inexpensive to produce and aesthetically pleasing.